Balance des substrats à l’exercice chez des patients infectés par le VIH 1 et présentant un syndrome lipodystrophique: Effet d’un réentraînement ciblé par la calorimétrie d’effort

Abstract

Aims Since AIDS-related lipodystrophy and its associated metabolic disturbances can be corrected by exercise targeted at the first ventilatory threshold ( V t1), we investigated the metabolic relevance of this V t1 in these patients and which are the effects of training targeted at the Lipox max determined by exercise calorimetry. Methods Twenty-one subjects (three women, 18 men, age: 46.05 ± 1.7 years, height: 1.72 ± 0.02 m; weight: 69.10 ± 2.47 kg) underwent a maximal exercise test for determination of the first ventilatory threshold ( V t1) and an exercise calorimetry. On the basis of this latter test dix of these subjects were trained for one year and were retested again at the end of this period. Results The crossover point (COP) defining the predominant use of carbohydrates is lowered from 43.47 ± 5.9 to 32.29 ± 4.4 watts while V t1 is at 76.33 ± 5.5 watts and the Lipox max is at 49.59 ± 4.53 watts. Although V t1 and COP are correlated ( r = 0.762; p < 0.01), their strong shift indicates that it is not the passage to a majority use of the carbohydrates which explains the beginning of hyperventilation and thus, V t1. The COP correlated with the serum triglycerides ( r = 0.5849; p = 0.0137) and with serum cholesterol ( r = 0.5119; p = 0.0357). In the 10 subjects that have been trained at the Lipox max, after one year, there is an increase in V O 2 max from 26.49 ± 1.36 to 31.13 ± 1.70 ( p < 0.01), parallel with a decrease in total cholesterol (from 2.58 ± 0.31 to 2.03 ± 0.15) and triglycerides (from 2.09 ± 0.35 to 1.98 ± 0.64). On this reduced sample, we cannot significantly evidence any improvement in body composition. Discussion and conclusions In HIV patients suffering from lipodystrophy, exercise calorimetry shows a tendency to an earlier use of carbohydrates and the PCX seems closely related to the blood lipid profile. In contrast to the general population, the ventilatory threshold does not coincide in these subjects with the COP. Endurance training targeted by exercise calorimetry seems to have effects quite similar to those of training targeted at V t1 and, in particular, improve lipid disturbances.